An astute strategy

If the sorry tale of debt and failed contracts at Cammell Laird has tarnished your perception of UK shipbuilding, then take a little solace from the quiet revolution taking place at BAE Systems’ Barrow yard.

The company is prime contractor for the Royal Navy’s three new Astute class nuclear submarines. With a brief including 14,000 individual requirements, the project could hardly be more demanding, and nothing short of a revolution in shipbuilding culture is under way with the aim of completing the vessels on time and to cost.

Bill Oliver, programme director at Barrow for platform sub-contractor BAE Systems Marine, makes no bones about the enormity of the challenge: ‘This is one of the most complicated projects ever undertaken by a group of engineers, even compared to building a space vehicle.’

The task is to build a uniquely versatile fighting tool, packing an array of weapons, a propulsion unit and living accommodation into a constricted space. The submarine must be capable of operating safely in extreme conditions of pressure and cold, and have a lifespan of 25 years.

As East-West relations have improved, so-called ‘attack class’ submarines no longer have to operate mainly in cold water, acting as escorts to the much bigger Trident subs that carry nuclear weapons. The Astute class will be called upon to undertake a wider variety of roles which adds more requirements to the design brief.

But perhaps the most challenging aspect for BAE Systems as prime contractor will be to pioneer new modular construction techniques and to build new relationships – both with the MoD as customer, and with the supply chain. Without these changes it will be impossible to deliver the Royal Navy’s largest attack submarine in record time and at a price the taxpayer can afford.

For the first time, the prime contractor will be responsible for all engineering support and repair work for eight ‘boat years’ after the vessels have been handed over to the navy.

In effect this period extends from the delivery of HMS Astute in 2005 to that of the last boat, HMS Artful, in 2009.

This creates an added incentive for the company to design a vessel that needs a minimal amount of support.

To achieve such time and cost savings, the prime contractor and its suppliers will have to work together to drive down costs. The transfer of design authority from the MoD to the prime contractor is the most significant change from the old – and more confrontational – way of doing things. In theory, this frees the prime contractor to try to get the best out of its supply chain.

To this end, sub-contractor BAE Systems Marine is discussing the possibilities of bulk discounting and combining equipment packages with its suppliers. Potential sharing of cost savings is also on the table. This has given everyone an incentive to do their best, rather than holding each other to ransom over the price of bespoke submarine components.

BAE aims to cut design time by 25% and production time by 30% compared to previous submarine projects. It usually takes about 12 million staff hours to build three submarines of this size, so the production phase is the main target for reducing costs.

If the new approach works, the HMS Astute will be built in six years – two years less than it took to deliver the smaller Trafalgar-class boats.

‘The philosophy is teamwork, and everyone in the team must face up to the responsibility to give the customer what he wants,’ says Oliver. ‘If we work together like this it means we all get the chance to do it again. ‘When you sit down with supply companies to tackle a problem and come up with an answer, you get a buzz.’

Rolls-Royce is supplying the nuclear propulsion units for all the Astute boats. It has already delivered the first reactor pressure vessel to BAE Systems. As with earlier designs, the plant has a 25-year lifespan. However, Astute will be fitted with a new long-life core, which will power the boat for its full service term, eliminating the need for expensive and time-consuming refuelling.

Now that it is responsible for designing, building and supporting the vessels, BAE Systems has pioneered a way of building submarines in modules. In other sectors, such as commercial shipbuilding and the offshore industry, this has proved the most effective way to cut production hours and project costs.

Oliver, who is also visiting professor of design at Newcastle University, was brought in as part of GEC Marconi’s bid for the Astute, prior to its merger with British Aerospace. His experience had been in the offshore industry, where modular building has been in use for many years.

The Astute’s hull will be built in ring-like sections. Meanwhile, rafts of components will be assembled simultaneously and floated in before the sections are welded together. ‘The trick is to wait as long as possible before we fit it together.

Traditionally the attitude has been: ‘We’ve got a huge amount of welding to do on this, so let’s get on with it.”

When the hull modules are welded together, the restricted access to the interior will multiply the time it takes to carry out further work by many times, he says. The concurrent process saves time and has allowed BAE to build a larger hull for less than it cost to build the smaller Trafalgar class. This in turn created space for 50% more weaponry.

The modular system puts the onus on engineers to design a vessel that takes advantage of opportunities for efficient production. ‘This was a huge cultural change for the designers,’ says Oliver. ‘It was no longer enough to design a great submarine. It had to be done in a way that made it easy and quick to fit together.

‘We had to make the team understand that putting in more effort at the early stages was the only way to reduce the overall costs.’

For the first time, a submarine has been designed solely on computer. Instead of relying on full-scale plastic models – which can cost well over £1m apiece – engineers are using virtual reality to manage the space inside the boat. A primitive virtual model is used in the early stages to allocate submarine space to various functions.

Production work can then begin before detailed plans have been completed. The first steel was cut for HMS Astute 14 months ago. A laser scan of the fabricated parts is used to produce an ‘as built’ model, which can be compared to the original virtual design. This reduces the amount of fitting work and the possibility of further change as the plans are released to production.

‘Because of the concurrency there is still a lot of detail we don’t know about yet and we have to manage and engineer our way through that,’ says Oliver.

So far, the project is on target and Oliver is confident things will stay that way, if only because of the expertise behind it.

‘We have people from the offshore and aircraft industry allied to the core team, which has years of submarine building experience. This team is unique and it is doing something very special. All this gives the lie to the perception of shipyards as outdated and inefficient. We are building a bigger submarine in 20% less time – how can that be inefficient?’

Sidebar: Triumph of the modular method

Astute is entering new waters by adopting the modular construction technique – a method many engineers were initially wary of.

The decision to use the modular technique to build a submarine involved not a little controversy and a calculated amount of risk.

Astute was born out of a plan to improve the combat capabilities of Trafalgar class submarines. An industry group comprising GEC Marconi, British Aerospace, Rolls-Royce and Vickers was asked to come up with a design that required minimal changes. Instead, the consequence was a complete rethink. A tender was issued in July 1994 and the bidders were VSEL and GEC Marconi.

Paul Tasker, BAE engineering director for Astute, who was working on GEC Marconi’s bid at the time, favoured the modular approach. Production labour was the main area where costs could be cut, and building the boat in sections was the best way to achieve this.

The standard submarine building method is to assemble the components inside the pressure hull after it is completed. Electronic equipment is fed in through the hatches and sometimes shoehorned into whatever space is available, making the final fit-out time-consuming.

‘The Germans and Swedes had pioneered modular build, so we looked at how we might apply it to our problem of controlling the amount of production labour,’ says Tasker.

Astute was broken down into nine hull sections and 11 main modules of equipment, including the reactor section, a 400-tonne command and control unit and more than 30 mini-modules.

While GEC Marconi took the modular build route, competitor VSEL, which had years of submarine building experience, opted for the traditional method.

The different techniques had to be reconciled when, a month before bids were due, GEC bought VSEL.

As part of the deal, the bid teams were kept separate for six months, after which the MoD selected the Marconi approach. This allowed time for talks on how the two teams would be brought together.

Many at VSEL felt modular construction was not proven and therefore risky. ‘This perception of risk deterred them. There was an attitude that there were better ways of doing things,’ says Tasker. ‘But all our efforts to build an affordable submarine were driven by the modular construction method.’

Talking people round took much work. ‘I could almost see the scales fall from one engineer’s eyes as I explained the advantages of modular build,’ Tasker says.

MoD cost estimates are usually calculated in direct proportion to weight – hence the drive towards smaller vessels. But the cost savings brought by the modular approach led to a decision to make Astute’s hull as big as possible – 10.7m in diameter, determined by the space needed to accommodate the new PWR2 reactor – to reduce the risks of the new technique.

The plan had been for the hull to bulge around the reactor, but this would have been more complicated and costly than extending the whole sub’s diameter and simplifying construction.

The bigger hull has allowed the Astute to carry 50% more weapons than the previous class.

Sidebar: Astute factfile

BAE won the £2bn contract to build three Astute attack class submarines in March 1997.

The design brief was for a submarine to undertake coastal, deep-sea and worldwide operations. Astute’s main roles will be anti-surface and anti-submarine warfare, but it will also be capable of land attack and mine laying.

The first steel for HMS Astute was cut in autumn 1999; it is due to enter service in 2005. Construction of the HMS Ambush will start later this year and work on HMS Artful is due to start in 2003.

The initial contract provides work for 2,800, at BAE Systems and its main sub-contractors, which include: Rolls-Royce (propulsion); Pilkington (masts); Thomson Marconi Sonar (sonar); Strachan and Henshaw (weapons handling and launch); and Ultra Electronics (weapon interfaces).

A further 2,200 will work on Astute throughout the supply chain, it is estimated.

At 7,200 tonnes and 97m long, Astute is 30% larger than its predecessor, the Trafalgar class, and is the largest nuclear powered attack class submarine ordered for the Royal Navy.

Astute will be armed with Tomahawk land attack missiles, Sub Harpoon anti-ship missiles and advanced Spearfish torpedoes.

The Strategic Defence Review, which calls for the maintenance of a force of 10 attack submarines, holds the promise of future purchases of Astute vessels.